Improvements for Heavy-Duty Engine and Vehicle Fuel Efficiency Test Procedures, and Other Technical Amendments

The National Highway Traffic Safety Administration (NHTSA) is finalizing minor technical amendments to the test procedures for heavy- duty engines and vehicles to improve accuracy and reduce testing burden. These amendments affect the certification procedures for fuel efficiency standards and related requirements. These amendments increase compliance flexibility, harmonize with other requirements, add clarity, correct errors, and streamline the regulations. Given the nature of these changes, NHTSA does not expect either significant environmental impacts or significant economic impacts for any sector.